Geophysical tomography in engineering geology: an overview

An overview of the tomographic interpretation method in engineering geophysics is presented, considering the two approaches of the deterministic tomography inversion, developed for rock elasticity analysis, and the probability tomography imaging developed in the domain of potential fields methods. The theoretical basis of both approaches is shortly outlined before showing a laboratory and a field application.Comment: 4 pages, 6 figures. Invited lecture at the 7th International Congress of the Brazilian Geophysical Society, Salvador, Bahia, Brazil, 28-31 October 200

An insight on the Proof of Orientifold Planar Equivalence on the Lattice

In a recent paper, Armoni, Shifman and Veneziano (ASV) gave a formal non-perturbative proof of planar equivalence between the bosonic sectors of SU(N) super Yang-Mills theory and of a gauge theory with a massless quark in the antisymmetric two-indexes representation. In the case of three colors, the latter theory is nothing but one-flavor QCD. Numerical simulations are necessary to test the validity of that proof and to estimate the size of 1/N corrections. As a first step towards numerical simulations, I will give a lattice version of the ASV proof of orientifold planar equivalence in the strong-coupling and large-mass phase.Comment: 14 pages, 3 EPS figures, uses REVTeX

QED Corrections to Hadronic Observables

When aiming at the percent precision in hadronic quantities calculated by means of lattice simulations, isospin breaking effects become relevant. These are of two kinds: up/down mass splitting and electromagnetic corrections. In order to account properly for the latter, a consistent formulation of electrically-charged states in finite volume is needed. In fact on a periodic torus Gauss law and large gauge transformations forbid the propagation of electrically-charged states. In this talk I will review methods that have been used or proposed so far in order to circumvent this problem, while highlighting practical as well as conceptual pros and cons. I will also review and discuss various methods to calculate electromagnetic corrections to hadron masses and decay rates in numerical simulations.Comment: 31 pages, Proceedings of Lattice 2017, extended version (the official PoS has only 20 pages

Localization of magnetic sources underground by a data adaptive tomographic scanner

A tomography method is proposed to image magnetic anomaly sources buried below a non-flat ground surface, by developing the expression of the total power associated with a measured magnetic field. By discretising the integral relating a static magnetic field to its source terms, the total power can be written as a sum of crosscorrelation products between the magnetic field data set and the theoretical expression of the magnetic field generated by a source element of unitary strength. Then, applying Schwarz's inequality, an occurrence probability function is derived for imaging any distribution of magnetic anomaly sources in the subsurface. The tomographic procedure consists in scanning the half-space below the survey area by the unitary source and in computing the occurrence probability function at the nodes of a regular grid within the half-space. The grid values are finally contoured in order to single out the zones with high probability of occurrence of buried magnetic anomaly sources. Synthetic and field examples are discussed to test the resolution power of the proposed tomography.Comment: 15 pages, 17 figure

Imaging polar and dipolar sources of geophysical anomalies by probability tomography. Part II: Application to the Vesuvius volcanic area

In the previous part I, we have developed the generalized theory of the probability tomography method to image polar and dipolar sources of a vector or scalar geophysical anomaly field. The purpose of the new method was to improve the core-and-boundary resolution of the most probable buried sources of the anomalies detected in a datum domain. In this paper, which constitutes the part II of the same study, an application of the new approach to the Vesuvius volcano (Naples, Italy) is illustrated in detail by analyzing geoelectrical, self-potential and gravity datasets collected over the whole volcanic area. The purpose is to get new insights into the shallow structure and hydrothermal system of Vesuvius, and the deep geometry of the tectonic depression within which the volcano grew.Comment: 7 pages, 10 figure

Strong dynamics, composite Higgs and the conformal window

We review recent progress in the lattice investigations of near-conformal non-abelian gauge theories relevant for dynamical symmetry breaking and model building of composite Higgs models. The emphasis is placed on the mass spectrum and the running renormalized coupling. The role of a light composite scalar isosinglet particle as a composite Higgs particle is highlighted.Comment: 28 pages, 1 figure. Invited review for IJMPA special issue "Lattice gauge theories beyond QCD.

Introduction to tensorial resistivity probability tomography

The probability tomography approach developed for the scalar resistivity method is here extended to the 2D tensorial apparent resistivity acquisition mode. The rotational invariant derived from the trace of the apparent resistivity tensor is considered, since it gives on the datum plane anomalies confined above the buried objects. Firstly, a departure function is introduced as the difference between the tensorial invariant measured over the real structure and that computed for a reference uniform structure. Secondly, a resistivity anomaly occurrence probability (RAOP) function is defined as a normalised crosscorrelation involving the experimental departure function and a scanning function derived analytically using the Frechet derivative of the electric potential for the reference uniform structure. The RAOP function can be calculated in each cell of a 3D grid filling the investigated volume, and the resulting values can then be contoured in order to obtain the 3D tomographic image. Each non-vanishing value of the RAOP function is interpreted as the probability which a resistivity departure from the reference resistivity obtain in a cell as responsible of the observed tensorial apparent resistivity dataset on the datum plane. A synthetic case shows that the highest RAOP values correctly indicate the position of the buried objects and a very high spacial resolution can be obtained even for adjacent objects with opposite resistivity contrasts with respect to the resistivity of the hosting matrix. Finally, an experimental field case dedicated to an archaeological application of the resistivity tensor method is presented as a proof of the high resolution power of the probability tomography imaging, even when the data are collected in noisy open field conditions.Comment: 8 pages, 7 figure

Finite-volume effects in (g−2)μHVP,LO(g-2)^{\text{HVP,LO}}_\mu

An analytic expression is derived for the leading finite-volume effects arising in lattice QCD calculations of the hadronic-vacuum-polarization contribution to the muon's magnetic moment, $a_\mu^{\text{HVP,LO}} \equiv (g-2)_\mu^{\text{HVP,LO}}/2$. For calculations in a finite spatial volume with periodicity $L$, $a_\mu^{\text{HVP,LO}}(L)$ admits a transseries expansion with exponentially suppressed $L$ scaling. Using a Hamiltonian approach, we show that the leading finite-volume correction scales as $\exp[- M_\pi L]$ with a prefactor given by the (infinite-volume) Compton amplitude of the pion, integrated with the muon-mass-dependent kernel. To give a complete quantitative expression, we decompose the Compton amplitude into the space-like pion form factor, $F_\pi(Q^2)$, and a multi-particle piece. We determine the latter through NLO in chiral perturbation theory and find that it contributes negligibly and through a universal term that depends only on the pion decay constant, with all additional low-energy constants dropping out of the integral.Comment: 5 pages, 2 tables, 1 figure, CERN-TH-2019-051, v2: Matches the published version. Fixed a sign mistake in a numerically suppressed contributio

k-String tensions and their large-N dependence

We consider whether the 1/N corrections to k-string tensions must begin at order 1/N^2, as in the Sine Law, or whether odd powers of 1/N, as in Casimir Scaling, are also acceptable. The issue is important because different models of confinement differ in their predictions for the representation-dependence of k-string tensions, and corrections involving odd powers of 1/N would seem to be ruled out by the large-N expansion. We show, however, that k-string tensions may, in fact, have leading 1/N corrections, and consistency with the large-N expansion, in the open string sector, is achieved by an exact pairwise cancellation among terms involving odd powers of 1/N in particular combinations of Wilson loops. It is shown how these cancellations come about in a concrete example, namely, strong coupling lattice gauge theory with the heat-kernel action, in which k-string tensions follow the Casimir scaling rule.Comment: Talk presented at the XXIX International Symposium on Lattice Field Theory - Lattice 2011, July 10-16, 2011, Squaw Valley, Lake Tahoe, Californi

Baryon currents in QCD with compact dimensions

On a compact space with non-trivial cycles, for sufficiently small values of the radii of the compact dimensions, SU(N) gauge theories coupled with fermions in the fundamental representation spontaneously break charge conjugation, time reversal and parity. We show at one loop in perturbation theory that physical signature for this phenomenon is a non-zero baryonic current wrapping around the compact directions. The persistence of this current beyond the perturbative regime is checked by lattice simulations.Comment: Minor changes, typos corrected; version accepted for publication in Phys. Rev.